Mapping global
flood risk

Fine-tuned global analytics

Professor Bates and his colleague Dr Jeff Neal of the University of Bristol’s Hydrology research group are responsible for the world’s first high-resolution simulations of flooding, borne out of a research programme that began in 2008.

With these modelling tools, the team typically map flood risk at resolutions of 30–90 metres (i.e. a single 30-metre grid cell, for example, represents 30x30 (or 900) square metres of land).

With the right underpinning data and over a small area of land, these tools have also mapped flood risk in megacities at a one-metre resolution.  In one UK case, mapping was done at just a 10-centimetre resolution.

It is not just the detail that is important, however. It is also the scale. Whilst many other models are able to simulate flood risk in high resolution at a local or regional level, Bristol’s flood-risk analytics can do so at the continental or global scale – and for any region of the world.

Previously, flood-risk analyses tended to focus on relatively small areas (river reaches a few tens of kilometres long) using detailed models and local data. They were also largely confined to the handful of developed countries with the resources to gather data using on-the-ground techniques, such as river and ground surveys. The earlier models that were capable of global and continental mapping tended to have resolutions of just one kilometre or more.

Supporting communities, industry and NGOs

“If you can think of a sector, we try and work with them,” sums up Dr Neal when discussing the widespread need for their analytics.

Indeed, the need to understand flood risk has never been greater for quite so many sectors, and especially as we confront the tough realities – and uncertainties – of climate change.

To date, the Bristol team have lent their flood-risk expertise to online tech companies, insurance firms, supply chain managers, financial authorities, humanitarian response agencies, and many more.

“These organisations need large-scale and detailed views of flood hazard and risk to provide a clear picture of where exactly flooding could strike and what the resulting damage might be,” says Dr Neal. Often, this support is provided through the team’s spin-out firm, Fathom, set up in 2013 to make cutting-edge methods of flood-risk modelling more widely available.

Notably, the research has helped humanitarian agencies prepare for disasters in a more targeted way. For instance, it has provided invaluable support for communities devastated by cyclones in eastern and southern Africa over recent years.

When Cyclones Idai and Eloise struck Mozambique in March 2019 and January 2021, for example, flood-risk maps compiled by the University of Bristol and partners helped UK Government-funded humanitarians predict which areas would be hit hardest and then plan supplies and staffing accordingly (see Emerton et al, 2020, for Cyclone Idai study).

Further, Bristol’s flood-risk intelligence has touched upon the daily lives of hundreds of millions of people around the world, although they’re unlikely to realise it. Through the spin-out Fathom, the team have supplied flood-risk data to Microsoft to assess risks to its global cloud infrastructure. This has helped Microsoft decide where to locate data centres, for instance, and how to optimise service delivery during extreme weather.

The World Bank also use the team’s data to assess national-scale flood risk in countries including Argentina, Belize, Bangladesh, Vietnam, Georgia and Armenia, and guide the Bank’s decisions on multi-billion USD investments and loans for infrastructure and disaster resilience projects. 

In addition, the research has contributed to compelling economic arguments to protect wild areas, namely floodplains in the US.  Working with the Nature Conservancy (TNC), one of the world’s largest environmental not-for-profit organisations, the Bristol researchers calculated that it makes far better financial sense to invest in floodplain protection now than to allow development on these natural areas of land – only to risk much costlier flooding in the future (Johnson et al., 2019).

At the end of 2023, Swiss Re, one of the world's leading providers of reinsurance, announced it was acquiring Fathom.  

“The mission remains the same; build the world’s best flood risk data,” Co-founder Dr. Andrew Smith said in an interview with SETsquared Bristol. “In our new home within Swiss Re we have the means to distribute what we have far more widely, so our models will get into many more people’s hands. We will also have the capabilities to accelerate and improve our products and roadmap. An exciting few years are ahead of us.” 

For more information on the commercial licensing of flood models derived from the Group’s work:

Beyond academic papers

“University research in our field is often fixated on small scales. We’ve made a huge step to scale up our research through to a product that is really useful,” reflects Dr Neal on the impact of the research.

“We’ve gone well beyond writing an academic paper or method.”

Professor Bates adds: “The fundamental scientific advances we’ve made are really important— to push forward knowledge and change how people understand things is at the core of what we do as scientists,” before providing, perhaps, the final word on detail and scale: “However, the  impact we’ve had on economic calculations and decisions that affect assets worth trillions of US dollars, and millions of people worldwide, is also what makes me very proud of our work.”